Isopropyl aminoethylmethyl phosphonite (NATO designation QL), also known as O-(2-diisopropylaminoethyl) O'-ethyl methylphosphonite, is a precursor chemical to the nerve agent

Nerve agent

Nerve agents are a class of phosphorus-containing organic chemicals that disrupt the mechanism by which nerves transfer messages to organs...

 VX

VX (nerve agent)

VX, IUPAC name O-ethyl S-[2-ethyl] methylphosphonothioate, is an extremely toxic substance whose only application is in chemical warfare as a nerve agent. As a chemical weapon, it is classified as a weapon of mass destruction by the United Nations in UN Resolution 687...

.

Uses in chemical warfare

QL is a component in binary chemical weapon

Binary chemical weapon

Binary chemical weapons or munitions are chemical weapons wherein the toxic agent is not contained within the weapon in its active state, but in the form of two chemical precursors, physically separated within the weapon...

s, mainly VX nerve agent. It, along with DF

DF

DF or df may stand for:Geography and politics* Distrito Federal or Federal District in two countries:** Mexican Federal District** Brazilian Federal District* Danish People's Party In computers...

(Methylphosphonyl difluoride), was developed during the 1980s in order to replace an aging stockpile of unitary chemical weapons. QL is listed as a "Schedule One" chemical by the Chemical Weapons Convention

Chemical Weapons Convention

The Chemical Weapons Convention is an arms control agreement which outlaws the production, stockpiling and use of chemical weapons. Its full name is the Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction...

.

Toxicity

QL itself is relatively non-toxic chemical. However, when reacted with sulfur, the corresponding sulphide of QL isomerizes

Isomerisation

In chemistry isomerisation is the process by which one molecule is transformed into another molecule which has exactly the same atoms, but the atoms are rearranged e.g. A-B-C → B-A-C . In some molecules and under some conditions, isomerisation occurs spontaneously...

into the highly toxic VX molecule.